I just got finished giving a talk to the graduate students of my department on "Forgotten milestones in the history of optics". The talk seemed to be very well-received, and I've already had faculty suggesting that I should give it again in the engineering department.
The talk was scheduled at 1 hour, and I prepared 45 slides. My only miscalculation was that I didn't take into account how long-winded I get when I'm talking about a subject I'm really passionate about -- I ended up speaking for 1h10m!
Here is the presentation: 2010_historyofoptics
Three of the four topics are essentially adapted from history of science posts I've put on this blog before, though the first one -- on Ibn al-Haytham -- is new.
If any departments are interested, I could be coaxed into coming to give a presentation... 🙂